Are there any side effects to taking fish oil?

No, the regular consumption of fish oils, either in fish or as a supplement, has little to no side effects. If too much fish oil is consumed at one time, adults might complain of nausea, but in my experience with children, the small doses we use do not cause this problem. Also, fish oil does not cause an increase in bleeding. As an anti-inflammatory agent, it can prevent the abnormal and excessive formation of blood clots but is not associated with the impairment of the body to normally form blood clots.